A '''dialect''' is a subset of a particular language that generally presents regional changes in pronunciation, grammar characteristics, and vocabulary, yet remains mutually understandable between two native speakers. An "accent" is an even smaller group of the language that generally only involves pronunciation.
As an illustration, some dialects of [[English]] include: American English (as distinct from British English or Austriallian English at large), Appalachian English, Black English Vernacular, New York City Dialect (sometimes considered only an accent), Cajun English, Texan.
National Map of Dialects of the United States [http://www.ling.upenn.edu/phono_atlas/NationalMap/NationalMap.html]
link showing dialects vs. accents [http://www.evolpub.com/Americandialects/EngDialLnx.html]